The structure and function of the major connective tissue macromolecules, collagen and proteoglycan, are being examined in animal models and human diseases. Samples of cornea, sclera, trabecular meshwork, and choroid are either radiolabeled in organ culture or cells derived from these tissues are grown and labeled in cell culture. The macromolecular products synthesized by these cultures are characterized using biochemical procedures. Alterations in the normal composition of collagens and/or proteoglycans may accompany or even be the basis for certain visually disabling diseases.